The incident is described as having started as a soldier-on-soldier attack at a medical building on base. Officials at a nearby hospital taking in wounded says wounds range from stable to extremely critical. All the wounded and killed are military personnel.

Lt. Gen. Mark Milley, head of the Army's III Corps at the post, said the shooter was a veteran of combat in Iraq who had "mental health issues and was being treated for that. At this time there is no indication that this incident is related to terrorism, although we are not ruling anything out and the investigation continues,'' Milley said.

According to Army officials, Lopez began firing with a semiautomatic pistol in the Fort Hood motor pool around 4:00 pm. He kept shooting until a military police officer approached him with her gun drawn, at which point he turned his gun on himself. His body was recovered in a parking lot.

Meanwhile, President Barack Obama Has Vowed That Investigators Will Get To The Bottom Of The Shooting, Seeking To Reassure The Nation Whose Sense Of Security Has Been Once Again Shaken By Mass Violence

President Barack Obama turns to leave after speaking about the shooting at Fort Hood

In a hastily arranged statement, Obama said he and his team were following the situation closely but that details about what happened at the sprawling Army post were still fluid. He said the shooting brought back painful memories of 2009, when 13 were killed at the same post in the deadliest attack on a domestic military installation in history.

"We're heartbroken that something like this might have happened again," Obama said. Offering thoughts and prayers to the entire Texas community, Obama pledged to do everything possible to ensure Fort Hood had everything it needed to weather a difficult situation and its aftermath.

"They serve with valor, they serve with distinction and when they're at their home base, they need to feel safe," Obama said. "We don't yet know what happened tonight, but obviously that sense of safety has been broken once again."

Several individuals, including Senator Joe Lieberman, General Barry McCaffrey, and others have called the 2009 event a terrorist attack. The United States Department of Defense and federal law enforcement agencies have classified the shootings as an act of workplace violence.

Days after the shooting, reports in the media revealed that a Joint Terrorism Task Force had been aware of a series of e-mails between Hasan and the Yemen-based imam Anwar al-Awlaki, who had been monitored by the NSA as a security threat, and that Hasan's colleagues had been aware of his increasing radicalization for several years. The failure to prevent the shootings led the Defense Department and the FBI to commission investigations, and Congress to hold hearings.